Hello I have been working with electrical sector since 1980 , timeserved electrical fitter, electrical machine tool fitter, test and development engineer for a large uk shower manufacturer, then an instructional officer in a prison ( a really interesting job). I have struggled to stay employed with multiple sclerosis, companies and organisations can not / will not suffer keeping anything other than fully efficient employees . Unfortunately our present govt has no time for sick people either or conditions that fluctuate. How ever I am never idle. We moved house , not touched from new in 1939 as one family owned, lived in till his death by the blind son. So a total refurb in many ways all plumbing all wiring all electrics, loft floored , access fitted, new kitchen walls out, drive on . concrete garage brought from london , base for same, new windows. Relocated the gas boiler ( my pal a gas eng training instructor tested that and supervised me doing it., chimneys out,walls out all new fences. Rewired our home, just built an extension so just about to fully test it and change the consumer unit, as building control need a minor works cert and I might as well do it properly. The house had been rewired to a fashion with odd pieces of twin & earth 1mm with the cores cut out for straps, sporadic sockets here and there with a nice consumer unit shoved in the most awkward and dark recess spot under the stairs. Well ms means I cant see in the dark well and I get get cramp I relocated that to a more civilised spot fortunately it had a nice 100a isolator so no need to involve the electricity company to de energise the circuit to move the tails.Live working 230v supply with 60a fuse is a mugs game it will evapourise any conductive components that touch. Leaving you at best temporarily dazed blinded and deaf and reeking of burnt copper and worst badly burnt or dead. Currently the 6mm twin & e changing to 4mm swa to the garage consumer unit at a cooker switch is fed by a 40a mcb on the old split board. The newer boards have an isolator and two rcd controlled banks of mcbs . I have recently acquired a fluke 1653b in call so will do the full suite of tests when I swap the consumer unit, the mk and bm metal clad consumer units would appear to allow me feed the garage by non rcd fed mcb. However I read that all wiring not mechanically protected by 3mm steel plate or 50mm of masonry what ever the zoning. However a short length of the 6mm is surface clipped to the consumer unit so I would be better feeding it via the main cu isolator rcd to mcb and if nuisance tripping the house from the garage changing the consumer unit rcd to a 16mA so it goes before the main house one.